Diaphragm-type pumps are employed in a wide variety of pumping applications. They are particularly well suited for pumping fairly viscous materials and materials which, while generally fluid, have a high solid content. It is a common practice to operate the diaphragms of pumps employed in this service by application of air pressure to the back side of the diaphragm elements employed. Further, it is a common practice to employ two diaphragm pumping elements in a single pump to effect double action pumping and wherein the two pumping elements are moved in unison by a connecting rod by first applying air pressure to one and then to the other. Such systems require the availability of a high pressure, high volume air supply which may not be readily available and, of course, such a source is both bulky and expensive. Furthermore, there is the requirement that tight seals be made where a diaphragm-to-diaphragm rod enters pump housings.
It is the object of this invention to provide an improved double diaphragm pump wherein the air source and sealing problems are eliminated.